1. Field of the Invention
This invention relates to a so-called short-distance photographing lens which can photograph objects from infinity to a very short distance.
2. Description of the Prior Art
Various types of short-distance photographing lenses called the microlenses or the macrolenses have heretofore been put into practice, but there have been no sufficient ones. These lenses are designed to provide the best performance for objects at a relatively short distance, but their image forming performance has unavoidably been deteriorated as the photographing magnification has become greater. It has, therefore, been necessary to mount an attachment lens exclusively for use for the correction of aberrations on a lens body in order to maintain an excellent image forming performance for short-distance objects for which the photographing magnification is one-to-one magnification. Also, the F-number of the conventional lenses has been on the order of 3.5 at best and they have been unsatisfactory as commonly used lenses in terms of the brightness.